We have demonstrated in the rat and squirrel monkey that N6, O2'- dibutyryl adenosine 3':5' cyclic phosphate (db cyclic AMP) is a potent antidote to amobarbital overdosage. There is no evidence to date that any analeptic agent administered intracerebroventricularly (ICV) shortens the time of arousal or decreases the mortality from central nervous system depressant drug overdosage. Db cyclic AMP is the first known antagonist of sedative, hyponotic and tranquilizer overdosage. The ability of db cyclic AMP to reduce amobarbital mortality from 46.6 percent to 3.3 percent in the rat is evidence of this paharmacologic interaction. Our study, therefore, is designed to determine (1) the dose of db cyclic AMP that will offer maximal protection; (2) the time interval within which db cyclic AMP must be administered to afford protection and prevent brain tissue damage. Behavioral and toxicity studies in the rat and rhesus monkey will be performed over a period of 180 days. We will measure, among other tests, liver function, amobarbital and cyclic AMP blood levels. Acute studies in the rhesus monkey will determine the use of already existing clinical supportive therapy combined with db cyclic AMP treatment to achieve maximal protection.